package com.atguigu.array;

import java.lang.Object;

public class Array<E> {
    private E[] data;
    private int size;

    /**
     * 构造函数，传入数组的容量capacity构造Array
     *
     * @param capacity 数组初始容量
     */
    public Array(int capacity) {
        data = (E[]) new Object[capacity];
        size = 0;
    }

    public Array(E[] arr) {
        data = (E[]) new Object[arr.length];
        for (int i = 0; i < arr.length; i++) {
            data[i] = arr[i];
        }
        size = arr.length;
    }

    /**
     * 无参构造函数，默认数组的容量capacity=10
     */
    public Array() {
        this(10);
    }

    /**
     * 获取数组中的元素个数
     *
     * @return 数组中元素个数
     */
    public int getSize() {
        return size;
    }

    /**
     * 获取数组的容量
     *
     * @return 数组容量
     */
    public int getCapacity() {
        return data.length;
    }

    /**
     * @return 判断数组是否为空
     */
    public boolean isEmpty() {
        return data.length == 0;
    }

    /**
     * 向数组中添加数据
     *
     * @param e 要添加的数据
     */
    public void addLast(E e) {
        add(size, e);
    }

    public void addFirst(E e) {
        add(0, e);
    }

    public void add(int index, E e) {
        //数组已满，进行扩容
        if (size == data.length) {
            resize(2 * data.length);
        }
        if (index < 0 || index > size) {
            throw new IllegalArgumentException("Add failed. Require index>=0 && index<=size");
        }
        for (int i = size - 1; i >= index; i--) {
            data[i + 1] = data[i];
        }
        data[index] = e;
        size++;
    }

    private void resize(int newCapacity) {
        E[] newData = (E[]) new Object[newCapacity];
        for (int i = 0; i < size; i++) {
            newData[i] = data[i];
        }
        data = newData;
    }

    public void swap(int i, int j) {
        if (i < 0 || i >= size || j < 0 || j >= size) {
            throw new IllegalArgumentException("index  is  illgeal");
        }
        E temp = data[i];
        data[i] = data[j];
        data[j] = temp;
    }

    @Override
    public String toString() {
        StringBuilder res = new StringBuilder();
        res.append(String.format("Array：size = %d,capacity=%d\n", size, data.length));
        res.append("[");
        for (int i = 0; i < size; i++) {
            res.append(data[i]);
            if (i != size - 1) {
                res.append(",");
            }
        }
        res.append("]");
        return res.toString();
    }

    public E get(int index) {
        if (index < 0 || index >= size) {
            throw new IllegalArgumentException("Get failed . Index  is  illegal.");
        }
        return data[index];
    }

    public void set(int index, E value) {
        if (index < 0 || index >= size) {
            throw new IllegalArgumentException("Get failed . Index  is  illegal.");
        }
        data[index] = value;
    }

    //查找数组中是否有元素e
    public boolean contains(E e) {
        for (int i = 0; i < size; i++) {
            if (data[i].equals(e)) {
                return true;
            }
        }
        return false;
    }

    //查找数组中元素e所在的索引，如果不存在e，则返回-1
    public int find(E e) {
        for (int i = 0; i < size; i++) {
            if (data[i].equals(e)) {
                return i;
            }
        }
        return -1;
    }

    public E remove(int index) {
        if (index < 0 || index >= size) {
            throw new IllegalArgumentException("remove failed . Index  is  illegal.");
        }
        E ret = data[index];
        for (int i = index; i < size - 1; i++) {
            data[i] = data[i + 1];
        }

        size--;
        data[size] = null;//垃圾回收
        if (size == data.length / 4 && data.length / 2 != 0) {
            resize(data.length / 2);
        }
        return ret;
    }

    //从数组中删除第一个元素，返回删除的元素
    public E removeFirst() {
        return remove(0);
    }

    //从数组中删除最后一个元素，返回删除的元素
    public E removeLast() {
        return remove(size - 1);
    }

    // 从数组中删除元素e
    public boolean removeElement(E e) {
        int index = find(e);
        if (index != -1) {
            remove(index);
            return true;
        }
        return false;
    }

    //从数组中删除全部元素e
    public boolean removeAllElement(E e) {
        boolean flag = contains(e);
        while (true) {
            if (!removeElement(e)) {
                break;
            }
        }
        return flag;
    }

    public E getLast() {
        return get(size - 1);
    }

    public E getFirst() {
        return get(0);
    }
}
